The difference between FCP and other plugins is that you're not relying upon other plugins to inform you of issues with the server. So with that FCP not updating via the Auto Update plugin automatically winds up flagging itself being out of date on your scheduled scans as an error, because it is paramount that
- Bug fixes on the tests get fixed
- Any new tests which may potentially impact you are correctly flagged.
The alternative is that FCP always downloads an updated list whenever it runs a scan. IE: It updates itself automatically
And besides, you can always hit ignore on that error and you won't be bugged anymore.
That scenario (severe risk) is actually handled via Community Applications itself (opt-in), and the warnings that it puts out are sure to catch your attention. CA handles that because even though FCP is quite commonly installed it still has nowhere near the install base that CA has.